Sam Mondry-Cohen, an assistant general manager for the Washington Nationals, has informed the club that he will not return after his contract expires at the end of this season. Mondry-Cohen, 34, has been with the Nationals since 2009, when he began as an intern, and is responsible for building the organization’s research and development department.

According to multiple people with knowledge of the situation, his decision to leave is centered on wanting to gather experience with another team and ultimately advance his career. When he told General Manager Mike Rizzo he was moving on, Mondry-Cohen did not have a next job lined up.

“My time with the Nationals has been a dream come true,” Mondry-Cohen said. “From 59 wins to a World Series ring, intern to assistant GM. But after 13 years in D.C., the best way for me to grow as a baseball executive is to find a new challenge in a new organization. And I’ve been fortunate to have the support and mentorship of Mike Rizzo throughout my baseball career. I never expect that to change.”

Mondry-Cohen is assistant general manager for baseball research and development for Washington. He is head of analytics, for short, but that also oversimplifies his role.